JPH07180555A - Cooling device for engine - Google Patents

Abstract

PURPOSE:To perform opening and closing of a thermostat valve with high responsiveness and to improve especially warming-up performance by a method wherein return passages for cooling water after a cylinder head and a cylinder block are cooled are interjoined and the thermostat valve is disposed at a confluence part between the two return passages. CONSTITUTION:An engine cooling device comprises cooling water passages 25 and 26 on the cylinder block 24 side; and cooling water passages 31 and 32 on the cylinder heads 29 and 30 side, and cooling water is circulated through the cooling water passages 25, 26 and 31, 32 through running of a water pump 23. In the engine cooling device, a second cooling water return passage 41 after cooling of a cylinder block is joined with a first cooling water return passage 39 on the water pump suction side through which cooling water after cooling of the cylinder heads is returned to the water pump suction side. A thermostat valve 43 having a temperature-sensitive part fronting on the first return passage 39 side and opening the second return passage 41 to the first return passage 39 when temperature in the first return passage 39 is increased to a value higher than a given temperature is arranged at a confluence part 42 between the two return passages 39 and 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device.

[0002]

2. Description of the Related Art In a water-cooled engine, cooling water is sent from a water pump to a cooling water passage provided in a cylinder head and a cylinder block for cooling.

Some of such cooling devices are designed to close the cooling water passage of the cylinder block when the cooling water temperature is below a predetermined value.

This is because a thermostat valve is provided in the cooling water passage of the cylinder block to block the flow of the cooling water in the cylinder block when the engine is cold, thereby improving the warm-up performance and during normal operation. By shutting off the flow of cooling water to keep the temperature inside the cylinder block at a predetermined value, the cylinder head is cooled accurately while suppressing overcooling of the cylinder block, thereby reducing friction with the piston. (JP-A-58-16271)
No. 6, etc.).

[0005]

However, in this conventional cooling device, in order to open and close the thermostat valve by the temperature of the cooling water in the cylinder block, the temperature sensing portion of the thermostat valve is connected to the outlet of the cooling water in the cylinder block. Although it is installed in the passage, the thermostat valve does not open and close properly with this.

That is, if the temperature sensing part of the thermostat valve is in the cooling water outlet passage of the cylinder block, no cooling water flows around the temperature sensing part when the thermostat valve is closed, Since it is in a stagnant state, the temperature inside the cylinder block cannot be accurately sensed.

For this reason, the opening of the thermostat valve is delayed, and the temperature around the cylinder liner becomes too high, or the thermostat valve opens before the temperature in the cylinder block reaches a predetermined temperature, resulting in good warming. There is a drawback that it is difficult to obtain machine performance.

An object of the present invention is to solve the above problems by opening and closing the thermostat valve by the temperature of the cooling water on the cylinder head side which is constantly flowing.

[0009]

SUMMARY OF THE INVENTION The present invention relates to an engine cooling device having a cylinder head side cooling water passage, a cylinder block side cooling water passage, and a water pump for sending cooling water to these cooling water passages. Return the cooling water after cooling the cylinder head to the suction side of the water pump 1st
And a second cooling water return passage for joining the cooling water after cooling the cylinder block to the first cooling water return passage. When the temperature sensing portion faces the first cooling water return passage side in the confluence portion and the cooling water temperature in the first cooling water return passage becomes equal to or higher than a predetermined temperature, the second cooling water return passage is provided in the first portion. A thermostat valve that opens the cooling water return passage will be provided.

[0010]

Therefore, the cooling water that has passed through the cooling water passage of the cylinder head flows through the first cooling water return passage, and the temperature sensing portion of the thermostat valve is provided in the first cooling water return passage. The temperature of the cooling water flowing through the cooling water passage, that is, the temperature of the cooling water after passing through the cylinder head opens and closes the thermostat valve with good response.

In this case, although the cooling water temperature after passing through the cylinder head and the temperature inside the cylinder block are different, when the cooling water temperature after passing through the cylinder head is low and the thermostat valve is closed, the cooling water in the cooling water passage of the cylinder block is When the cooling water temperature after passing through the cylinder head becomes high and the thermostat valve is opened, the cooling water also flows into the cooling water passage of the cylinder block.

Therefore, according to the setting of the opening temperature of the thermostat valve, good warm-up performance is ensured, the temperature in the cylinder block is maintained at the required temperature, and the temperature of the cylinder liner etc. is prevented from becoming too high. To be done.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a V-6 engine, FIG.
4 is a cooling path diagram thereof. The right bank 22 of the engine 20 is on the front side of the engine (front side of the vehicle), and the left bank 21 is
Is bank offset to the rear of the engine.

The discharge side of the water pump 23 installed at the front end side of the engine 20 has inlets 27, 28 and left and right sides of cooling water passages 25, 26 formed in the banks 21 and 22 on the left and right of the cylinder block 24 from the center of the bank. Cooling water passages 31, 32 formed in the cylinder heads 29, 30 of the
Is connected to the inlet portions 33 and 34 of the.

The cooling water passage 25 of the cylinder block 24,
26 pass around each of the cylinders 35 and are joined at an outlet 36 at the rear of the block.

Cooling water passage 3 of cylinder heads 29, 30
1, 32 pass through the respective combustion chambers, intake ports, exhaust ports, etc., and outlets 37, 38 are formed at the rear of the head.

A first cooling water return passage 39 is connected to the outlet portions 37, 38 of the cooling water passages 31, 32 of the cylinder heads 29, 30.

The first cooling water return passage 39 is bent toward the center of the bank immediately from the outlet 37 side of the cooling water passage 31 of the cylinder head 29 of the left bank 21 which is bank offset to the rear side of the engine. The cylinder head 30 of the right bank 22 that is bank-offset to the front side is formed to extend toward the outlet portion 38 side of the cooling water passage 32 and join the outlet portions 38.

The passage area of the first cooling water return passage 39 is smaller on the outlet portion 37 side of the upstream cooling water passage 31 and gradually expands to the inside (engine side) to remove the position of the cylinder head 29. It is formed so as to enlarge the downstream. FIG. 5 shows the structure of the first cooling water return passage 39.

A downstream side of the first cooling water return passage 39 extends along the right bank 22 toward the front side of the engine, and is located at the suction side of the water pump 23 and at the inlet passage 55 of the radiator 40 installed at the front side of the engine. Connected, the outlet passage 56 of the radiator 40 is connected to the suction side of the water pump 23.

On the other hand, a second cooling water return passage 41 is connected to the outlet portions 36 of the cooling water passages 25 and 26 of the cylinder block 24, and the second cooling water return passage 41 is connected to the first cooling water return passage 39. In addition, the cooling water passages 31 and 32 of the cylinder heads 29 and 30 are joined between the outlet portions 37 and 38.

A thermostat valve 43 is interposed in the confluence portion 42. 5 to 9 show the structures of the confluence portion 42 and the thermostat valve 43.

In the first cooling water return passage 39 of the confluence portion 42, a predetermined volume portion 44 is formed in which the passage 39 is expanded toward the engine side and the center is offset, and this volume portion 44 is formed.
An opening is provided on the upper surface of the. A cover 46 having a pipe port 45 is attached to this opening, and the second cooling water return passage 41 is connected to the pipe port 45.

The thermostat valve 43 has a first valve 47 and a second valve 48 assembled to a support frame 49, and a wax case 50 filled with wax, a piston 51, and a wax case 50, respectively. Integrated valve 52
And a spring 53.

The thermostat valve 43 is inserted into the volume 44 of the first cooling water return passage 39 on the side of the wax case 50 serving as a temperature sensing portion, and the flange 54 of the support frame 49.
Is applied to the periphery of the opening of the volume 44, and the cover 46
It is fixed by attaching.

The first valve 47 of the thermostat valve 43 is
When the temperature of the cooling water flowing through the first cooling water return passage 39 reaches a predetermined temperature (a temperature higher than the valve opening temperature of the radiator thermostat valve 57 described later), the wax in the wax case 50 begins to expand and presses the tip. Piston 51
The valve 52 is opened by pressing down the wax case 50 against the spring 53. The second valve 48 of the thermostat valve 43 is for safety, and the valve 52 is opened when the cooling water temperature rises to the upper limit temperature.

The first valve 47 is arranged upstream of the second valve 48 in the first cooling water return passage 39 (cylinder head 29 side).

A thermostat valve 57 is provided in the outlet passage 56 of the radiator 40 connected to the suction side of the water pump 23, and when the cooling water temperature on the suction side of the water pump 23 is below a reference temperature (for example, 82 ° C.). The outlet passage 56 is closed, and when the reference temperature is reached, the outlet passage 56 is opened.

Numeral 58 designates a line for the passenger compartment heater
Reference numeral 9 indicates a line for the oil cooler.

With such a structure, when the cooling water temperature is low, such as when the engine is cold, the thermostat valve 43 of the confluent portion 42 of the first and second cooling water return passages 39 and 41 is used.
Also, the thermostat valve 57 of the outlet passage 56 of the radiator 40 is closed.

At this time, the cooling water discharged from the water pump 23 flows through the cooling water passages 31 and 32 of the left and right cylinder heads 29 and 30, and circulates to the water pump 23 through the first cooling water return passage 39. At the same time, the flow of cooling water in the cooling water passages 25, 26 of the cylinder block 24 is blocked. Therefore, the temperature inside the cylinder block 24 rises quickly.

When the temperature of the cooling water passing through the inside of the first cooling water return passage 39 reaches a predetermined temperature, the second cooling water return passage 4
Thermostat valve 43 of the merging portion 42 (first valve 4
7) is opened, but when the temperature is lower than this, the thermostat valve 57 of the outlet passage 56 of the radiator 40 is opened, and the cooling water is cooled through the radiator 40.

As a result, the cylinder heads 29 and 30 are accurately cooled, while the cylinder block 24 is not overcooled and the temperature inside the cylinder block 24 is maintained at the required temperature.

Then, when the temperature of the cooling water flowing through the cooling water passage 31 of the cylinder head 29 and passing through the inside of the first cooling water return passage 39 reaches a predetermined temperature, the thermostat of the confluence portion 42 of the second cooling water return passage 41. The valve 43 (first valve 47) is opened, the second cooling water return passage 41 is opened to the first cooling water return passage 39, and the cooling water from the water pump 23 is the cooling water passage of the cylinder block 24. It will be distributed to 25 and 26.

Since there is a temperature sensing portion of the thermostat valve 43 in the cooling water flowing from the cooling water passage 31 of the cylinder head 29 to the first cooling water return passage 39, the temperature of the cooling water causes the thermostat valve 43 to respond well at the set temperature. It can be opened and closed properly.

Therefore, while the high warm-up performance is ensured, the temperature inside the cylinder block 24 is maintained at an appropriate temperature, so that the friction with the piston is sufficiently reduced and good combustibility is obtained. It is possible to improve fuel efficiency and reduce emissions. Further, when the temperature of the cooling water after cooling the cylinder head 29 becomes equal to or higher than a predetermined temperature, the cylinder block 24 is cooled, so that the temperature of the cylinder liner and the like does not rise excessively.

FIG. 10 shows the circulation flow rate of the cooling water in each part when the thermostat valves 43 and 57 are open. The amount of cooling water in the right cylinder head 30 is larger than that in the left cylinder head 29 because the return resistance of the first cooling water return passage 39 is large. Further, if the cooling water of the cylinder block 24 is cut off, the amount of cooling water of the cylinder heads 29, 30 increases accordingly.

When the cooling water temperature rises to the upper limit temperature, the safety valve 48 of the thermostat valve 43 is opened, and high safety is obtained.

[0040]

As described above, according to the present invention, the cylinder head side cooling water passage, the cylinder block side cooling water passage,
In an engine cooling device having a water pump for sending cooling water to these cooling water passages, a first cooling water return passage for returning the cooling water after cooling the cylinder head to the suction side of the water pump is provided, and after cooling the cylinder block. A second cooling water return passage that joins the cooling water to the first cooling water return passage is provided, and a temperature-sensing portion is provided at the confluence portion of the first and second cooling water return passages. A thermostat valve is provided which faces the return passage and opens the second cooling water return passage to the first cooling water return passage when the temperature of the cooling water in the first cooling water return passage exceeds a predetermined temperature. So
The cooling water of the cylinder block can be cut off and circulated properly, the warm-up performance can be improved, and the cylinder block can be maintained at an appropriate temperature to reduce friction, improve fuel efficiency, and reduce emissions.

[Brief description of drawings]

FIG. 1 is a plan view of an engine according to an embodiment.

FIG. 2 is a cooling path diagram of the embodiment.

FIG. 3 is a cooling path diagram on the front side of the engine.

FIG. 4 is a cooling path diagram on the rear side of the engine.

FIG. 5 is a plan view of a first cooling water return passage.

FIG. 6 is a plan view of a cover of a merging portion.

FIG. 7 is a plan view in which a thermostat valve is incorporated in a merging portion.

8 is a cross-sectional view taken along the line AA of FIG.

9 is a cross-sectional view taken along the line BB of FIG.

FIG. 10 is a flow rate characteristic diagram.

[Explanation of symbols]

 20 Engine 21 Left Bank 22 Right Bank 23 Water Pump 24 Cylinder Block 25, 26 Cooling Water Passage 29, 30 Cylinder Head 31, 32 Cooling Water Passage 36-38 Outlet 39 First Cooling Water Return Passage 40 Radiator 41 Second Cooling water return passage 42 Confluence part 43 Thermostat valve 44 Volume part 46 Cover 47 First valve 48 Second valve 50 Wax case

Claims (1)

[Claims] 1. A cooling device for an engine, comprising a cylinder head side cooling water passage, a cylinder block side cooling water passage, and a water pump for sending the cooling water to these cooling water passages. A first cooling water return passage for returning to the water pump suction side is provided, and a second cooling water return passage for joining the cooling water after cooling the cylinder block to the first cooling water return passage is provided.
At the confluence of the first and second cooling water return passages, the temperature sensing portion is exposed to the side of the first cooling water return passage so that the cooling water temperature in the first cooling water return passage becomes equal to or higher than a predetermined temperature. An engine cooling device, characterized in that a thermostat valve for opening the second cooling water return passage to the first cooling water return passage is provided.